中文摘要：

利用低压MOCVD系统在弯曲度值不同的蓝宝石衬底上生长了GaN基LED外延结构并制作芯片。测量了芯片的主要电学和光学参数,并分析了衬底弯曲度值对芯片性能的影响。分析结果表明：存在弯曲度的衬底预先弛豫了外延层中的部分应力,改善了外延层的质量,从而提高了LED芯片的性能。随着衬底弯曲度值的逐渐增加,下层GaN对有源层中InGaN材料的压应力作用不断减小,导致芯片的主波长逐渐发生蓝移。

英文摘要：

GaN-based light emitting diodes（LEDs） were grown on the sapphire substrates with different bow values by low pressure metal organic chemical vapor deposition（MOCVD）.LED chips were fabricated and the optic and electronic parameters were characterized.The influence of different bow values on the performances of LED was investigated.The analysis results show that the substrates with bow could relax part of the stress in the epilayer beforehand,which improved the quality of epilayer.Hence,the performances of the LED chips got better.During the growth of LEDs,the InGaN material in the active layer suffered the compressive stress that resulted from the underneath GaN layer.With the increase of bow values,the compressive stress that acted on the InGaN material decreased,which leads to the blue shift of the dominant wavelength.